Testing 2n2222 Method using Wall-wart?

[EliteGamer83]

Mhm.... I'm stopping back in, doubt anyone remembers me.

I'm still no professional electrical engineer here so I could use some help.

If I want to test out the sound-reactive LED's using a headphone out in place of the speaker terminal (+, -), and a wall-wart @ 5v to supply the voltage for the LED(S), where do I connect the ground wire from the wall-wart in the circuit?

Whatever help is much appreciated.